GB/T 8647.3-1988 Chemical analysis of nickel - Molybdenum blue spectrophotometric method for the determination of silicon content
Some standard content:
National Standard of the People's Republic of China
Nickel-- Determination of silicon content- Molybdenum blue spectrophotometric method
Nickel-- Determination of silicon content- Molybdenum blue spectrophotometric method This standard applies to the determination of silicon content in nickel. Determination range: 0.0005%~~0.0025%. UDC 669. 24
GB8647.388
This standard complies with GB1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
The sample is dissolved in nitric acid and evaporated to a thick slurry, in which insoluble silicon dioxide is added with hydrofluoric acid to generate soluble monosilicic acid. At pH 1.0-1.5, silicon and ammonium molybdate form silicomolybdate yellow heteropoly acid, which is extracted with n-butyl alcohol benzene in a sulfuric acid medium. The organic phase is reduced to molybdenum blue with hydrazine sulfate and stannous chloride, and its absorbance is measured at a wavelength of 630nm on a spectrophotometer. 2 Reagents
The water used for preparing solutions and analysis is double distilled water. After preparation, the reagents are stored in plastic bottles. 2.1 Nitric acid (1+1), high purity.
2.2 Sulfuric acid (1+3), high purity.
2.3 Sulfuric acid (7+93), high purity.
2.4 Hydrofluoric acid (1+1), high purity.
2.5 Saturated boric acid solution, high purity.
2.6 Ammonium molybdate solution (10%): Weigh 10g of high purity ammonium molybdate [(NH4Mo,0·4H0] and dissolve it in 80mL of hot water and cool. Dilute to 100mL with water and mix.
2.7 Sulfate diamine solution (0.25%), high-grade pure. Prepare with high-purity sulfuric acid (1.5+98.5). 2.8 Stannous chloride solution (10%): Weigh 10g of high-grade pure stannous chloride (SnCl2H,0) and dissolve in high-purity hydrochloric acid (1+1) and dilute to 100mL, mix. Prepare before use.
2.9 Citric acid solution (50%), high-grade pure. 2.10 n-Butanol.
2.11 Silicon standard storage solution: Weigh 0.2142g silicon dioxide (≥99.9%) into a platinum crucible, add 5g high-grade pure anhydrous sodium carbonate, mix well, cover, place in a muffle furnace at 400℃, heat to 900℃, melt for 1h, take out, cool, wash the outer wall of the crucible with water, place in a polytetrafluoroethylene cup, add 100mL hot water to dissolve at low temperature, and cool to room temperature. Transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. Immediately transfer to a dry plastic bottle for storage. This solution contains 100ug silicon per mL. 2.12 Silicon standard solution: Transfer 50.00mL silicon standard storage solution (2.11) into a 1000mL volumetric flask, dilute to scale with water, mix well, and transfer to a dry plastic bottle. This solution contains 5ug silicon per mL. 3 Instruments
3.1 Spectrophotometer.
Approved by China National Nonferrous Metals Industry Corporation on January 11, 1988 410
Implemented on January 1, 1989
3.2 The carrier gas closed evaporator device is as shown in the figure:
GB 8647.3-88
1-Glass cylinder (s250mm); 2-Beaker (500mL); 3-Electric furnace, 4-Graphite plate; 5-Polytetrafluoroethylene volute; 6-Beaker (1000mL); 7-Infrared lamp; 8, 9--Gas washing bottle; 10-Tap water pump 4 Analysis steps
4.1 Sample treatment
Weigh 10g of nickel sample into a clean 200mL beaker, rinse with double distilled water for 2 to 3 times, remove the water layer and wash twice with anhydrous ethanol, dry at low temperature, cool to room temperature for use. 4.2 Sample quantity
Weigh 1.000g of sample (4.1).
4.3 Blank test
Carry out a blank test together with the sample.
4.4 Determination
4.4.1Place the sample (4.2) in a 30mL platinum crucible (or polytetrafluoroethylene crucible), slowly add 8mL nitric acid (2.1), cool and dissolve, after the reaction stops, move the crucible into a carrier gas seal, heat and dissolve (below 100°C), evaporate the solution to a thick paste (blank evaporate to about 0.5ml), take out and cool.
4.4.2Add water to 10mL, add 0.2mL (about 4 drops) of hydrofluoric acid (2.4), stir with a plastic rod until the solution is clear, place in a plexiglass dustproof box, and place at 30±5°C for 30min. 4.4.3 Take out the crucible, add 8mL of saturated boric acid solution (2.5), stir well, place in a plexiglass dustproof box, leave for 15min, add 2.5mL of ammonium molybdate solution (2.6), stir well, adjust to pH 1.0-1.5 with nitric acid (2.1) (check with precision test paper of pH 0.5-5.0), and place at 20-30℃ for 15min.
4.4.4 Add 5mL of citric acid solution (2.9), stir well. 4.4.5 Transfer the solution to a 125mL separatory funnel, rinse the crucible with 15mL of sulfuric acid (2.2) and transfer to a separatory funnel, add 14ml of water, shake well, add 20mL of n-butanol (2.10), shake for 1min, let stand to separate, and discard the aqueous phase. 4.4.6 Add 15mL of sulfuric acid (2.3) to the organic phase, shake for 30s, let stand to separate, and discard the aqueous phase. Repeat this operation once. 4.4.7 Add 5 mL of hydrazine sulfate solution (2.7) and 0.5 mL of stannous chloride solution (2.8) to the separatory funnel, shake for 30 seconds, let stand to separate, discard the aqueous phase, transfer the organic phase to a 25 mL dry colorimetric tube, dilute to scale with n-butanol (2.10), mix, let stand to clarify, and transfer part of the solution to a 1 cm colorimetric tube.
4.4.8 Take the blank solution accompanying the sample as a reference, measure its absorbance at a wavelength of 630 nm on a spectrophotometer, and find the corresponding silicon content from working curve 1.
4.5 Drawing of working curve
GB 8647.3-- 88Www.bzxZ.net
Take 0, 1.00, 2.00, 3.00, 4.00 and 5.00 mL of silicon standard solution (2.12) and place them in a set of 30 mL platinum crucibles respectively. The following is carried out according to 4.4.2 to 4.4.7. With the reagent blank solution as the reference, measure its absorbance at a wavelength of 630nm on the spectrophotometer, and draw a working curve with the silicon content as the horizontal axis and the absorbance as the vertical axis. Calculation of analysis results
Calculate the percentage of silicon content according to the following formula:
m,×10
si(%) =:
Where: ml --
6Allowable difference
The amount of silicon found from the working curve, gs
Sample volume,.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. %
0. 000 5~~0. 001 5
>0. 001 5 ~ 0. 002 5
Additional remarks:
This standard is under the technical jurisdiction of Beijing General Research Institute of Mining and Metallurgy. Beijing General Research Institute of Mining and Metallurgy and Jinchuan Nonferrous Metals Company are responsible for drafting this standard. This standard is drafted by Shanghai Smelter Design Institute. The main drafters of this standard are Yu Zhenyang and Zhu Rulin. Allowable difference
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB12876 "Nickel Chemical Analysis Method" will be invalid. 412
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